The overall purpose of the Biostatistics Core is to provide support in the areas of research design, data entry and management, statistical analysis, and presentation of results for the projects and researchers in the Early Caries Detection and Intervention program project. In addition, the Core will seek to develop new statistical methodology as the need arises. The existence of the Core also assurances that any unforeseen statistical analyses or design problems will immediately be brought to the attention of professionals with expertise in these areas. Details on the specific methodologies and statistical analyses for each project appear in the individual proposals.